IADR Abstract Archives
Neutral Electrolyzed Water Controls Contamination in Dental Unit Water Lines
Objectives: Prevention of nosocomial infections and provision of safe medical care are extremely important in view of increase in compromised hosts due to aging population as well as prevalence of opportunistic and emerging infectious diseases. In dentistry, microbial contamination of not only treatment instruments but also dental unit water lines (DUWLs) are problems. We focused on effect of neutral electrolyzed water (NEW) and reported its inhibitory efficacy on contamination in DUWLs using simulator (Okubo et al, Heliyon, 2020). In this study, to further verify the effect of NEW, we investigated bacterial contamination in water collected from DUWLs in use of dental treatment with and without NEW before and after microfilters were replaced.
Methods: Water was collected from 3-way syringes of #1 NEW-installed chairs (without microfilter replacement), #2 NEW-uninstalled chairs (with microfilter replacement), and #3 NEW-uninstalled chairs (without microfilter replacement) after 1-minute flushing and disinfection of the syringes with 70% ethanol. Tap water was used as a control. Numbers of heterotrophic bacterial colonies in water sample were counted by incubation on R2A agars and bacterial ATP amount was measured using a commercial kit. Surface of microfilters were observed by scanning electron microscopy (SEM). Numbers of viable bacteria on DUWLs walls were determined by colony counting, of which anaerobic bacteria were identified by DNA sequence analysis.
Results: Number of heterotrophic bacterial colonies and ATP amount in water from DUWLs were significantly higher in #3 than in #2 and #1.Observation of microfilter surface by SEM showed adherence of bacterial-like layer. Heterotrophic and anaerobic bacteria (Kocuria rhizophila and Propionibacterium acnes) were detected on inner wall of DUWLs.
Conclusions: These results demonstrated that heterotrophic bacteria were present in tap water itself and some of them passed through microfilter and grew within DUWLs. In preventing DUWL contamination, NEW installation would be effective as well as microfilter replacement.
Methods: Water was collected from 3-way syringes of #1 NEW-installed chairs (without microfilter replacement), #2 NEW-uninstalled chairs (with microfilter replacement), and #3 NEW-uninstalled chairs (without microfilter replacement) after 1-minute flushing and disinfection of the syringes with 70% ethanol. Tap water was used as a control. Numbers of heterotrophic bacterial colonies in water sample were counted by incubation on R2A agars and bacterial ATP amount was measured using a commercial kit. Surface of microfilters were observed by scanning electron microscopy (SEM). Numbers of viable bacteria on DUWLs walls were determined by colony counting, of which anaerobic bacteria were identified by DNA sequence analysis.
Results: Number of heterotrophic bacterial colonies and ATP amount in water from DUWLs were significantly higher in #3 than in #2 and #1.Observation of microfilter surface by SEM showed adherence of bacterial-like layer. Heterotrophic and anaerobic bacteria (Kocuria rhizophila and Propionibacterium acnes) were detected on inner wall of DUWLs.
Conclusions: These results demonstrated that heterotrophic bacteria were present in tap water itself and some of them passed through microfilter and grew within DUWLs. In preventing DUWL contamination, NEW installation would be effective as well as microfilter replacement.